Temperature compensated shock resistant fuse



oct. 18, 1955 H. W HOUSTON ETAL TEMPERATURE COMENSATED SHOCK RESISTANTFUSE Filed June 5, 1948 III/[IIIA VIII/'lill' l L 5 Sheets-Sheet I Fig.L21- Oct. 18, 1955 H. w. HOUSTON ETAL 2,720,835

TEMPERATURE COMPENSTED SHOCK RESISTANT FUSE Filed June 3, 1948 Eig. a- 55 Sheets-Sheet 2 Fi 4 M Ef 94 i FEU mf l s @V295 Syvum/Mom H W. Hmunn TT- E.- Urban 354g IL K Allj. DTL l 3 #mf 0, @im

Oct. 18, 1955 H. w. HOUSTON ET A1. 2,720,835

TEMPERATURE COMPENSATED SHOCK RESISTANT FUSE United States Patent -nlTEMPERATURE CMPENSATEE) SHOCK RESISTANT FUSE Application .lune 3, 1948,Serial No. 30,864 8 Claims. (Cl. IGZ-70) Urbany, Los Angeles,

This invention relates to an atmospheric pressure responsive fuse, andis designed to provide a fuse for detonating an explosive charge,particularly an aerial bomb. The fuse functions automatically when thecharge attains a determined altitude. The invention provides alternativeoperating mechanisms for operation on ascent and descent of the charge.It also provides shock-resistant means t prevent accidental functioningof the fuse due to vibration or impact. There is also providedcompensation means to counteract atmospheric pressurevariations due totemperature variations. tures of the fuse are the sectional case forenclosing and supporting the operative mechanism, the restraining meansfor releasably latching the iring means, the pressure operated means forreleasing the restraining means, the

shock-resistant means to prevent accidental release of the restrainingmeans, and the compensation means responsive to temperature variations.

While there have been illustratedin the drawings tiled herewith andhereinafter fully described several specific embodiments of theinvention, it is to be distinctly understood that the invention is notconsidered to be limited to said specific embodiments and that its scopeis defined by the claims appended hereto.

In the drawings:

Fig. 1 is a side elevation of the fuse and charge, partly in section;

Fig. 2 is a vertical section in the direction of the arrows;

Fig. 3 is a vertical section in the direction of the arrows;

Figures 4 through 8 are sectional views in planes perpendicular to thelongitudinal axis of the instrument as indicated by the lines 4 4; 5 5;6 6; 7 7 and 8 8, respectively, of Figure 2.

Fig. 9 is a fragmentary vertical section, similar to the upper portionof Fig. 3, showing the thermostatic adjusting elements modified byelevation of temperature;

Fig. l0 is a vertical section similar to Fig. 3 showing a modified formof the fuse;

Fig. ll is a fragmentary vertical section of another modified form ofthe fuse; Fig. 12 is a detail view of one of the dogs of the latchingmeans;

Fig. 13 is a detail view of the tiring pin.

As illustrated in the drawings, the fuse has a tubular case forenclosing and supporting the operating mechanism, and comprising live,cylindrical, co-axial elements inter-engaged in lapped joints forfacilitating assembly and cemented together by suitable means whenassembled. A cap 1 for closing the top of the case is seated on anelement 2 and has a neck 3 projecting downwardly into the upper end ofelement 2 and suitably axially spaced relative to an interior peripheralflange 4 of element 2 to secure the rim of a flexible element 63therebetween. Element 2 is seated on an element 5 which has a neck 6projecting upwardly into the lower end of element 2. Element on the line2 2 of Fig. 1,

on the line 3 3 of Fig. 2,

The particularly novel fea- 2,720,835 Patented Oct. 18, 1955 5 is seatedon an element 7 which has a neck 8 projecting upwardly into the lowerend of element 5 and suitably axially spaced relative to an interiorperipheral shoulder 9 on element 5 to clamp the rim of a flexiblediaphragm 14. Element 7 is seated on an element 10 and has a neck 11which projects downwardly into the upper end of element 10. Element 10has a longitudinal key lll-a received in key-way 11-a in neck 11 toprevent relative rotation of elements 7 and 10. The lower end of neck 11is spaced from a peripheral shoulder 12 on element 10 to clamp acircular disc 24. Element 10 has an exterior peripheral groove 13 toreceive the adjacent end of a container 44.

Between the neck 8 of the element 7 and the shoulder 9 of the element 5,there is mounted a circular, concaveconvex flexible diaphragm 14, of anysuitable material, such as rubber, having a peripheral flange 15congured to be engaged by the co-acting faces of neck 8 and shoulder 9when the element 5 is seated on the element 7. The diaphragm 14 is somounted in the case as to effect a gas-tight joint therewith. Thediaphragm 14 has a central, thickened and bored portion 16 on which ismounted a plate 17 supporting a clevis 18, and having a threaded bolt 19passed through the diaphragm 14 and a plate 20, and provided with a nut21 for clamping the diaphragm 14 between plates 17 and 20 in a gas-tightjoint therewith. The plate has formed integral therewith a dependingcage 22 having on its lower end a latch 23 in the form of a ring coaxialwith diaphragm 14.

Between the neck 11 of the element 7 and the shoulder 12 of the element10, there is mounted a circular disc 24 clamped securely in positionwhen the element 7 is seated on the element 10. Disc 24 has a centralbore 25 and a pair of upstanding lugs 26 at the sides of bore 25,respectively, in which are pivoted a pair of dogs 27 in the upper endsof which are journaled rollers 2S. Slidably received in the bore thereis a firing pin 29 having a peripheral bevel 30 on its upper end and aperipheral groove 31 adjacent thereto having upper and lower bevelledcam faces 32 and 33. Dogs 27 have bevelled noses 34 intruded into groove31 and engaging face 32 of firing pin 29 when the dogs 27 are relativelyproximately disposed by the rollers 28 latched by the circumscribingring 23, as shown in Fig. 3. The pin 29 has a second peripheral groove35 inferior to groove 31. Formed integrally with the disc 24, there is atubular housing 36, coaxial with disc 24, and into which depends thefiring pin 29 which has on its lower end a peripheral flange 37. A coilspring 38 about pin 29 is confined between disc 24 and flange 37,biasing pin 29 downwardly. Pin 29 has, on its lower extremity, adetonating point 39. Threaded on the lower end of housing 36 is a casing40 in which is mounted a primer 41 for a booster charge 42 in casing 40.Booster charge 42 is disposed in a main explosive charge 43 for the ringof which the novel fuse is designed, and which is packaged in acontainer 44, the open neck 45 of which is seated in groove 13 ofelement 10 of the case of the fuse, lashing 46 serving to unite the caseand container 44.

Carried on the upper end of the neck 6 of the element 5 of the casethere is a spider 47 (see Figure 5) having convex ends 48 seated againstthe element 2, and depending lugs 49 in which are pivoted a pair of bellcranks 50 having forked ends 51, embracing pin 52 in clevis 18, and armsS3 carrying inertia masses 54. Mounted on the spider 47 by bolts 55,there is a V-shaped, bimetallic, thermostatic member 56 comprising twoarms 57 and 58 extending upwardly in element 2 of the case. Arm 58 isprovided on its upper end with a bracket 59 supporting a secondV-shaped, bimetallic, thermostatic member 6l) comprising two arms 61 and62, arm 61 being attached to bracket 59. As shown in Fig. 3, the members56 and 60 are so dimensioned and related,

3 that member 56 comprehends member 60, the arms 57, 58, 61 and 62 beingnormally parallel.

Between the neck 3 of the cap 1 of the case and the flange 4 of theelement 2, there is mounted a circulai exible diaphragm 63 of materialsuch as rubber 'having a peripheral liange 64 configured to beengaged bythe co-acting faces of neck 3 and ange 4 when the cap -1 is seated Vonthe 'element 2. The diaphragm 63 is lso mounted in the case as to effecta gas-tight joint therewith.

The diaphragm 63 is formed as a frusto-conical member having 'a central,thickened and bored portion 65 to which is fastened a plate 66 having athreaded bolt 67 passed through portion 65 and a Washer 68 thereon andprovided with 'a nut 69 for clamping the diaphragm 63 between plate 66and washer 68 in a gas-tight joint therewith. The plate 66 is providedwith depending lugs 70 (see Figure '3) in which is pivoted one arm of abell crank 71, the 'other 'arm of which is pivoted to a link 72pivotally mounted on a bail 73 mounted in arm 57 of the thermostaticmember 56. Bell crank 71-is pivoted intermediate its arms to one arm ofa Second bell crank 74 which is received in the slotted upper end ofAarmV 57 and pivoted on a bail 75 mounted in arm 57. The other arm ofbell crank 74 is pivoted to a link 76 pivoted on a bracket 77 mounted onthe upper end of arm 62 of the thermostatic member l 60.

, As shown in Figs. 3 vand 9, when the 'parts 'are -assembled asdescribed, the diaphragm 63 is dshed, its degree of deforma-tiondepending upon the position of plate 66 determined by the positionsofthe thermostatic arms 57 and 62 and their associated linkage.

A Cap 1 has an orifice 78 to provide communication fork the interior ofcap 1 with atmosphere.

The element 2 Yhas an` orifice79 (Figures 2 -and 4) toprovidecommunication for the interior of the casing between thediaphragms 14 and 63. Snugly fitted in 'the orifice 79, therevis anipple 80` of -a plug 81 having a threaded bore '82 in which is threadedarbolt 83 with slotted head S4 seatedAin recess 85 of plug 81. Thenipple 80, Ethe recess 35 'and the bore 82 are co-axial. Bolt 83 has acentral bore 86 Twith which connects a radial bore S7 opening throughtheperiphery of bolt 83 to its en'd adjacentghead 54. The lparts are sodesigned and Vrelatedthat when the bolt 83 is set up kin plug 81 s othat head S4 is seated in recess 85, the bore 87 is closed toA seal thatportionofthe 4interior of the casing between diaphragrns '14 and 63, andthe -head'8'4 is disposed interiorly of the periphery of element 2, andthat when bolt 83, uhscrewevd by turning head A84 'with a lsuitabletool, Yis retracted sufficiently to withdraw bore 87 from bore 'S2 vandinto recess 85, vand head v84 is exterior of the periphery of element 2,the bores 86 and 87 afford lcommunication for the interior of the casingto atmosphere.

The ,elernent and neck A1-1 of the element 7 have co-axial transverseorifices 8S and 89Figure4 '8, -in which ils slidably jdisposed `arsafety pin 90 which is Vpassed through orice`su91so disposed in Llugs26 on discl24 lals to pass pin 90 Athrough `groove 35 in firing lpin29,. j he safety pin 90 has an arm 92 normal to pin 90 and exterior oftheperiphery of the'case (Figs. l, 3 kand 8). l A T he element 7 has apair of relatively spaced Vtransverse parallelly disposed orifices 93and sockets 94 co-axial lwithrorificesl 93, respectively. A hairpindetent 95 has itsvlegs 96 slidable through orifices 93, Vand their ends:seated in sockets 94. Orifices 93 -and socketsl94 are so disposed Vasto position the legs 496 about the dogs 27 when the dogs 27 are disposedin 'ring 23. The bight of detent 95, connecting the legs 96, hasswingable lthereon a tongue or strap v98 received against the peripheryof the case when the detent -95 is mounted in the case, and confined byaring 99 slidable on the case. It will vbe noted (Fig. l) that the arm92 of safety-pin 90 Yis `confined by the `detent 95, so that detent 95must be removed to permit removal of pin 90, and (Fig. 2) that ring 99is disposed over orifice 79 when psitihed to confine tongue 98.

In Fig. l0, there is shown a modified form of the fuse in which thethermostatic members, exible diaphragm and linkage therefor areeliminated. In this form of the device, the element `2 has an innerperipheral ange 4-a spaced from the lower end of neck 3 of cap 1.Between neck 3 and ange 4-a, there is mounted appartition 100 in agas-tight Vjoint therewith and forming the upper end of the chamber inthe casing extending from ythe diaphragm 14 to partition 100. Partition100 has a central boss 101 projecting upwardly and a socket 1'02 on itslower lside in which is seated, in a gas-tight joint, a capillary tube103 having adminute bore 104. The boss 101 has a minute bore 105connecting socket 102 with the interior of cap 1. Except for theabove-described elements the form of the device shownin Fig. 10 isidentical with the form shown Yin Figs. l to 9..

In Fig. ll, there is s hown a modifiedl formof the device in which aIliexible diaphragm 14-z is designed vto flex upwardly to raise thelatch 23. In this Vform, a shoulder V9-.a ofA an element l5-a is seatedon neck 8 of. the element 7 and the peripheral flange 15u-a of v'thediaphragmM-a is seated on a shoulder 9-71 of the element S. A sleeve 6a,fitted in the upper end 'oflellemen't 5-a land projecting therefrom, isseated on flange 15-a. Element 2-a is fitted "bout the projectlngportion of sleeve A6--a and is seated on Athe element S-a. The sleevel6-a comprises tw'o Asemicylindrical portions for a purpose presentlyexplained. `The spider 47 is mounted on `the ltop of sleeve 46-al andhas lugs 2l9-a somewhat longer than 'lugs 49 of the vfo'rin shown inFigs. 1 to 9. "On lugs t9-1, there are pivdted two bell cranks 'S0-a,which are rever'selyl disposed relative to elevis 18 "from Athedisposition of bell eranks 50,"t`9 prevent accidental raising ofthe ring23. O'ther'parts of this, form ofthe Vfuse areidentieal'withcorresponding parts of the form shown'in Figs. ll to 9. Y

The method o'f assembling |the abovede`s`erib`ed k'parts iwill "n'ow beexplained. The thermostatic member '56wit'h Lr`n`eni`t5`er A60 and the'linkager'noited thereon lis 'mounted on the spider 47. The bell c'rilks`50 'reinonted on `lugs 49 lof the spider 47, 4and pin 52 passed'through c'le'vs 1S lai'id forked ends '51 'of cranks 50, attachingclev'is `18, plate 17 andbolt 19, under spider 47 rSpider 47 'is `thenseated o`n eck`6 VAof element 5. The diaphragm is'then mounted on bolt19 and cage 23 Vis mounted on bolt v"I9, 'me "prrs being pfpn'y reiste@by 'sifihgp ntzi on bolt *19,A and -the flange 15 of vdiaphragm 14'being s'e'ted on shoulder i9 lof "element 5. Element 2, :withpliig 814irio'il'ritie'i therein, isthen seated fonielemeit 5, the ehfds '48 ofspider`47 as well afsiiieck 6`of element'S'and thelw'e end of element 2being 1properly leiiiitedto form 'a g'as- `ti`ght joint. `The -flexible'diaphragm 1'63 `is 'mounted V'on plate J66 'dfth'e liiikagefonythrnis'tfati'c `r`ne1i1berf56 ``rid its iian'g'e'l seated on 'ia`ge4jf'el'eileit *2. Cap 1`is appliedto upper endif'eleriie'nt 2, ifs'iek 3engagifgthe iiange 64, and the parts cemented 'to fin "a ygastifgh't'joint l The dogs 27 are mounted on fof'dis'c 2/4 'which is then seted'nnek Jll'oifeleinei1`t 7 4Ail'dlceilrte'd thereto. Detent is theninserted `into element 7 "embracing -dogs 27.` Pin 2 9 with spriiig38thereonis'iiisetedthrbgh "hoiis'irig bore 25,

braced by detent 95 and pin 29 is held by pin 90, the noses 34 engagethe upper edge of cam face 32 and rollers 28 are suciently proximate forring 23 to embrace them slightly above their axes. It is obvious that asdogs 27 are moved into adjusted position by seating element 7, therollers 28 rotate as their axes become aligned with the transverse axisof ring 23, and that dogs 27 are moved away from legs 96 of detent 95and toward pin 29 which causes noses 34 to cam upwardly pin 29suiciently to free pin 90 which is then removed. Element is then appliedto element 7, key 10-a seating in key-way 11-a and shoulder 12 bearingon the disc 24.

Detent 95 is removed, pin 90 is inserted and detent 95 replaced,engaging arm 92 of pin 90 (Fig. 1). Bolt 83 is threaded in bore 82 ofplug 81 suiciently for its head 84 to be received in recess 85.

Ring 99 is placed about element 2 to confine tongue 98 of detent 95.Casing 40 with detonator 41 and booster charge 42 may be threaded onouter end of housing 36 immediately prior to applying the fuse to theexplosive charge.

In assembling the form of the fuse shown in Fig. 10, after element 2 hasbeen seated on the element 5, the partition 100 is seated on the flange4-a of element 2. The tube 103, which had been mounted in socket 102 inboss 101 of partition 100 before partition 100 is seated on flange 4a,is disposed within element 2. When thus assembled the parts are cementedto form a gas-tight joint. Cap 1 is then applied to upper end of element2, the neck 3 of cap 1 bearing on the partition 100, and the parts arecemented.

The method of assembling the form of the fuse shown in Fig. l1 will nowbe explained.

When the dogs 27 have been assembled with pin 29 on disc 24 and inelement 7, as above described, element S-a is mounted on the element 7.Latch ring 23, diaphragm 14-a and clevis 18 are then assembled bysetting up nut 21 on bolt 19. Ring 23 is then moved downwardly bypressure on clevis 18 and bolt 19 until dogs 27 are disposed as shown inFig. l1, and flange -a of diaphragm 14-a is seated on shoulder 94b ofelement S-a. One of the semicylindrical portions of the sleeve 6-a isthen mounted in the element 5-a and on flange 15-a, to support thespider 47 which is then mounted thereon so that clevis 18 is disposedbetween lugs 49-a. Bell cranks 50-a are then applied to clevis 18 andpivoted in lugs 49-a. It is to be understood that the portion of sleeve6-a, previously mounted, is so disposed as to afford access betweendiaphragm 14-a and spider 47 to permit mounting bell cranks Slt-a. Theother portion of sleeve 6-a is then mounted in element S-a and on flange15-a, and element 2-a is disposed about the upper end of sleeve 6-a andseated on element S-a the parts being cemented to form a gas-tightjoint. It is to be understood that before the spider 47 is mounted onsleeve 6-a, the thermostatic element 56 and its associated parts aremounted on the spider 47. The remainder of the assembling is aspreviously described. i

From the foregoing description of the details of construction of thefuse, its use and operation can be understood. The operation of the formof the fuse shown in Figs. 1 to 9 will now be described. This form ofthe fuse is designed to function on reduction of atmosphereic pressureviz. on ascent. With parts assembled as shown in Figs. 1 to 8, the fuseis conditioned for use. Before 'the fuse is connected with container 44,ring 99 is moved upwardly on the case, off of orifice 79 and tongue 98,and hair-pin detent 95 is withdrawn, releasing safety pin 90. It will benoted (Fig. 3) that when the dogs 27 are embraced by latch 23, both legs96 and pin 90 are free for unobstructed withdrawal. However, should theoperative parts have become accidentally displaced so that dogs 27 arenot held in latched position by ring 23, the dogs 27 will bear againstlegs 96 to impede their withdrawal and that when legs 96 are withdrawn,the dogs 27 cammed out of groove 31 by upper cam face 32 will releasefiring pin 29 which is projected by its spring 38 to engage safety pinin groove 35, thereby impeding removal of pin 90. Should it be foundthat pin 90 is not freely withdrawable, the fuse is shown to be inunusable condition and cannot be used, until tiring pin 29 is re-cocked.When theparts are properly disposed, pin 90 can be readily withdrawn.After the detent has been removed, safety pin 90 is allowed to remain inplace as a precaution to prevent accidental release of tiring pin 29.The bolt 83 is then screwed out suiiciently to put the chamber betweendiaphragms 14 and 63 in communication with atmosphere through bores 86and 87, the chamber being otherwise sealed. It will be noted thatwithdrawal of hairpin detent 95 opens oritices 93 through which thechamber between diaphragm 14 and disc 24 is put in communication withatmosphere. Thus it is obvious that diaphragm 14 is subjected to uniformatmospheric pressure on both sides and is thereby immobilized. When thedevice is at that altitude at which the desired atmospheric pressureobtains for charging the chamber between diaphragms 14 and 63, the bolt83 is set up in plug 81 to close bore 87, thus completely sealing thechamber between diaphragms 14 and 63. The fuse is then attached to thecharged container 44 and safety pin 90 is withdrawn. The fuse is nowarmed and ready to function. When the device is elevated, above. thealtitude at which it is armed, to that altitude at which the atmospherepressure is sufficiently reduced below that of the pressure in the upperchamber, the diaphragm 14 is deformed, since the chamber below diaphragm14 is charged through orifices 88, 89 and 93 with the atmosphere ofreduced pressure. It is to be understood that the parts are constructedand related so that at that point in ascent of the device at which thepressure differential reaches the desired amount, the diaphragm 14 willbe flexed downwardly out of its normally upwardly curved position todepress ring 23 sufficiently to pass below the axes of the rollers 28which are pressed outwardly by action of spring 38 and cam surface 32 onnoses 34 of dogs 27, tending to force ring 23 downwardly suciently torelease dogs 27 from pin 29 which is projected downwardly by spring 38through tube 36, its point 39 striking detonator 41 firing boostercharge 42 and exploding charge 43.

It will be noted (Figs. 2 and 3) that as the diaphragm 14 is normallycurved upwardly and cannot be moved further upwardly and the ring 23 isso related to diaphragm 14 as to latch dogs 27 when diaphragm 14 isnormally curved upwardly, the ring 23 cannot be moved upwardly torelease the dogs 27. There is, therefore, no need for means to preventaccidental lifting of ring 23. However, since the fuse functions byflexing of the diaphragm 14 downwardly to depress the ring 23 to releasethe dogs 27, the device is provided with means to prevent accidentalexng of the diaphragm 14 downwardly, as by vibration to which the devicemay be subjected. The inertia masses 54 are so connected to the flexiblestructure by the crank arms 53 as to counteract any tendency of thediaphragm 14 and ring 23 to move downwardly, since any impulse byvibration tending to move the diaphragm 14 and ring 23 downwardly tendsto move masses 54 downwardly which, through crank arms 53, tend to movediaphragm 14 and ring 23 upwardly.

In the foregoing description of the fuse it was explained that the fusefunctions when the differential of the pressures on the opposite sidesof diaphragm'14 reaches the desired amount. Itis obvious, therefore,that for the desired proper functioning of the fuse the pressure in thesealed chamber must be maintained uniform. Since the mass of atmospherein the sealed chamber is subject to pressure variations incident totemperature variations, the device is provided with thermostaticautomatic means for varying the volumetric capacity of the sealedchamber to maintain uniformity of pressure of the mass of atmospheresealed therein. In the form of the device shown in Figs.

1 t9, this means comprises the thermostatic members 56 and 60, theiiexible diaphragm 63 and the linkage therefor. As clearly shown inlFig. 9, when the 'temperature in the sealed chamber is elevated to adegree to increase the pressure of the atmosphere in the chamber due toits expansion by heating, the Varms 57 and 58 of the thermostaticTrnember S6 are cause to move apart, and the arms 6l 'and 62 of 'themember 60 move likewise. Since member 60 is movable bodily with arm 58,the movement of arm 62 is augmented. The deflection of arm 57 movesbell-crank 74 bodily relative to the axis of bolt 67 in the center ofdiaphragm 63, and'consequently moves bell-crank 7-1 likewise, tending tolift diaphragm 63. Simultaneo'usiy this movement 'of arm 57 cau'se'slink 7-2 to rock crankarm 7L tending to lift diaphragm 63.Simultaneously, the movement of arm 62 causes link 76 to rock bellcrank7'4 raising bell-crank 71 bodily, tending to lift diaphragm 63. -It isobvious that this raising of diaphragm 63, increasing the volumetriccapacity of the chamber, compensates the expansion to maintain thedesired pressure in the chamber. It is obvious lthat the reversemovements are produced by reduction of temperature Ycausing reduction ofpressure due Vto 'contraction by cooling.

As above pointed out, in the form of the device shown in Fig'. l0, thethermostatic compensating means is eliminated. This form of the deviceis provided with the capillary tube 103 to provide means to maintainconstant pressure of `'the atmosphere in the sealed chamber. Increasedtemperature in the sealed chamber, causing expansion of the atmosphereproduces evacuation of that portion of the atmosphere, through tube 103,to compensate the expansion to maintain uniform pressure on diaphragm14. Reverse operation, on cooling, effects the desired result'. 'It isobvious that the cross-sectional area 'of bore 104 and length of tube103 are designed to efiect `the above described results. Since thecompensations by this means are effected at 'determined speeds, 'it isto be understood that the functioning of ythis form of the fuse isdirectly affected by the rate-of-climb whereby the pressu-redifferential is effected. Should the speed of ascent of `the device beconsiderably accelerated, the degree of compensation'is consequentlyreduced, and compensation is increased at reduced rate of speed.

A-As :above pointed out, in the 'form of the fuse shown in Fig. l1, thefiexible diaphragm 'Ilka is designed to fiex upwardly and-it is lobvious'that i'n this form of the device -the diaphragm 14-a is flexed by thepressure exerted by the atmosphere in the chamber below ldiaphragm l14-awhen it becomes superior to the pressure in the lsealed chamber abovethe diaphragm 14-a, the device functioning on descent. It is to beunderstood that lthe compensati-ng means shown-in Figs. 3 and 10 can beused alternatively with either Yof the forms of the -fus'e -shown in-Figs 3 and 1-1.

We claim:

1 In :a lfuse -for `detonating -an explosive charge, the combinationof atubular case, a transverse closure 4sealing yone end of said-case; afiexible transverse sealing wall intermediate the ends of Vsaid casedividing said case into first and second Vco-axial chambers, said casehaving an orifice therein providing a single rport for the first of saidchambers between said closure and said wall, and a plu'- "rality oforifices therein providing aplurality of ports'for the ysecond of saidchambers; a Vremovable closure for sealing said orifice providing saidsingle port; a'transverse closure for the other end of said case, andspaced-from said wall-to define said second chamber; firing pin meansvfor detonating'the charge, said firing pin means being supportedAon--said seco'nd closure, means biasing -said firing pin means tofiringlposition; a dogmounted in Ysaid second chamberandpivotable from'a firstposition engaging and holding said 'firingpin means againstmovement to 'firing fposition, and ya `second fposition releasing saidfiring :pin means, and a latch ringconnected with said'sealing wall,

said latch ring normally engaging said dog to hold the same in firstposition and movable with said sealing wall in response to a change inldifierential pressure within and without -said first chamber, torelease said dog. I I

2f. lIn a pressure-differential-responsive fuse, a tubular casing, wallsclosing the respective ends of said casing, a fiexible diaphragm acrosssaid casing between said walls and dividing said casing into first andsecond chambers, a firing pin reciprocably mounted inthe end wall of onesaid chamber, spring means urging said pin into firing movement, a dogoperable in a first position to hold said pin retracted against theaction of `said spring means, means connected withvsaid diaphragm andengageable with said dog -in an undefiect'ed position of said diaphragmto hold said 4dog in -first position and movable with said diaphragm inresponse to a predetermined pressure differential between said chambersto release said dog, valve means operable to selectively connect onesaid chamber with the atmosphere, and means including atemperature-responsive element in said last-named chamber to vary thevolume thereof directly with temperature to 'thereby maintain constantthe pressure in said last-named chamber.

3. Ina pressure-differential-responsive fuse, a tubular casing, firstand second walls closing the respective `ends of said casing, a fiexiblegas-tight diaphragm in said casing and, with said walls, dividing saidcasing into first and second chambers, a firing .pin axially mounted insaid second wall for movement from a retracted position to firingposition, a spring urging said firing pin into firing position, aplurality of dogs mounted on said second wall about said firing pin, forpivotal movement in respective radial planes from a first posit-ionengaging and holding said firing pin in retracted position to a secondposition releasing said pin, a ring secured to said diaphragm andnormally surrounding and Aholding said dogs in first position andmovedby and with ysaid diaphragm in response to a predetermined pressuredifferential between said 'chambers to -free said dogs and release saidpin for firing movement, and a capillary tube in said vfirst chamberconnecting ythe interior thereof with the ambient atmosphere. 4. In apressure-differential actuated fuse, a tubular casing, first 4and secondwalls closing respective ends of said casing, a yflexible gas-tightdiaphragm in said casing and, in cooperation with said walls, dividingsaid casing Airito -first and second chambers, a firing pin axiallyslidable 'in and Athrough said second wall from a retracted to a 'firingposition, spring means urging said pin into firing position, a pluralityof dogs carried by said second wall and pivotable from a 'first positionengaging and holding said pin 'reti-acted, "to a second position freeingsaid pin -for firing movement, safety means carried by said dia-'phra'gm engaging and holding all said dogs in first posi- 'tion 'whensaid diaphragm is undefiected, said safety 'means 'being moved by saiddiaphragm to release said dogs Vwhensaid 'diaphragm is defiected Vinresponse to a predeterminedipre'ssre difference between said chambers,and aflev'erarm weighted Yat one end and connected with VSaid diaphragmat the other, whereby to oppose movement of said diaphragm otherwisecaused by shocks and jars.

v5. 'In 'a 'pressure-differential responsive fuse, a closed casing, apartition in 'said casing comprising a fiexible 'gas-tight diaphragmdividing said casing into first and second chambers, a firing `pi`n'slidably mounted in said L'second chamber from 'a 'retractedto a firingposition,

spring means urging said 'pin into firing position, avplurality of dogsmounted about sa'id pin for pivotal kmove- 'merit in respective planesradially of said Ypin from a 'first position engaging Aand 4holding saidpin retracted, to a second position releasing 'said pin for ringmovement, `a ring secured to said diaphragm, said ring enlg'agin'g saiddogs to hold the same in first position when lsaid diaphragm -is inundefiected position and movable 'with said diaphragm to release saiddogs in response to 'a predetermined pressure difierential between said#chanbers, 'and valve means `operable to selectively open 'o'r closelsaidifirst chamber to the -ambient atmosphere.

6. A fuse as recited in claim 5, a second exible diaphragm in the wallof said irst chamber, and bimetallic thermostatic means in said iirstchamber and connected with said second diaphragm to ex the same inresponse to temperature changes in said first chamber and therebymaintain substantially constant the pressure therein.

7. A fuse as recited in claim 5, said dogs being two in number and ondiametrically opposite sides of said ring pin, a iirst U-shaped safetypin with its bight portion outside said casing and its legs extendingthrough apertures in said casing to engage and hold respective dogs iniirst position, a second safety pin extending through an aperture insaid casing and engaging and holding said tiring pin retracted, saidsecond safety pin having a bent end normally held between said casingand bight portion of said first safety pin.

10 8. A fuse as recited in claim 7, a tongue having one end secured tosaid bight portion, and a band encircling said casing and simultaneouslyholding said tongue against said casing and sealing oif communicationbetween said valve means and the ambientatmosphere.

References Cited in the file of this patent UNITED STATES PATENTS583,633 Roesch June l, 1897 1,617,674 Dieter Feb. l5, 1927 1,830,869Charles Nov. 10, 1931 2,330,873 Doe Oct. 5, 1943 2,422,548 Hebard June17, 1947 FOREIGN PATENTS 165,108 Great Britain June 30, 1921

